Combining flash particle radiography with 12C6+ and 4He2+ mixed-ion species treatment

Speaker: Martin Schanz
Institution: Los Alamos National Laboratory, United States of America

Abstract

High energy flash proton radiography is a powerful diagnostics technique for high energy -density physics that is capable of resolving ultra-fast processes on the ns scale in dense matter with unprecedented micrometer spatial resolution. However, it is also capable of providing a very precise density reconstruction of the material investigated as well as superior image contrast in ion-optically thin objects even for small density differences (below 1%). Recent studies have mostly focussed on the applicability of this technique for medical imaging in general and for improving the current treatment planning techniques by combining X-ray and proton images. However, the high speed of data acquisition, the accuracy of this technique, and the ability to use different ion species make it an ideal candidate for combined flash treatment and patient imaging. We propose a novel combined treatment and imaging approach based on flash therapy with mixed-ion species (12C6+ and 4He2+), which could enable fast patient treatment with simultaneous high-speed patient imaging. Using, e.g., a 280MeV/u, 5.17Tm magnetic rigidity mixed beam for flash treatment, 12C6+ and 4He2+ would yield ranges in H2O of 15.2cm and 45.6cm, respectively. The 4He2+ beam exiting 20cm of H2O still has a remaining kinetic energy of 199MeV/u and experiences lateral scattering of about 12.3mrad. A suitable system would consist of two ion-optical particle radiography lenses with the first one being used for precise mapping of the desired particle distribution on the patient (tumor) using multi-leaf collimation while the second lens would serve as an imager to produce an instant image and density map of the treated area (see Figure). We have performed proof-of-concept MC simulations (GEANT4) and imaging of medical phantoms to demonstrate the applicability of this technique for the medical community.

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